Towel dispenser

ABSTRACT

The invention relates to a towel dispenser ( 10 ) such as a paper towel dispenser comprising a housing ( 12 ) in which a paper roll and an issuing device ( 50 ) are arranged. Said issuing device can AC be controlled by a sensor ( 38 ). In order to simplify the operation and to increase the reliability of the towel dispenser, the invention provides that the sensor ( 38 ) is configured as a capacitive sensor.

BACKGROUND OF THE INVENTION

The invention relates to a towel dispenser, in particular a paper toweldispenser, comprising a housing in which a receiver such as a roller forthe towel or several towels and an issuing device for said towel(s) isprovided, with the issuing device being actuatable by a sensoractivatable from the housing exterior. The invention further relates toa towel dispenser, in particular a paper towel dispenser, comprising ahousing in which on the one hand the dispensed product, such as a paperroll, and on the other hand an issuing device are arranged.

Towel dispensers, in particular paper towel dispensers, whose issuingdevice reacts to a light-sensitive sensor are known. To prevent thesensor from reacting to light changes as caused by persons walking past,for example, the sensor in the known dispensing devices must be arrangedon a lateral housing panel so that defined light conditions are assured.This however entails the drawback that persons wishing to operate thetowel dispenser only find the laterally arranged sensor after a lengthysearch. Also, these types of dispensing devices are often arranged withinsufficient clearance from side walls, so that the amount of light isinsufficient to dependably trigger operation.

A paper towel dispenser is described in U.S. Pat. No. 4,406,421. Fromits housing exterior, a lever is accessible via which rack and pinioninside the housing mesh such that a section of the paper towel isaccessible via a issuing opening.

WO97/29671 describes an electrically actuatable paper towel dispenserthat can be actuated by means of a photographic sensor.

In order to obtain liquid soap from a dispenser, in particular in thearea of operating theaters, without the need to directly touch thedispenser, a capacitive sensor is used in accordance with DE 34 00 575A1, the one electrode of which runs directly in the area of the liquiddispensing opening. The counter-electrode is formed by the space onwhich the person wishing to use the dispenser is standing.

The problem underlying the present invention is to develop a dispensingdevice of the type mentioned at the outset such that its operation issimplified and its dependability increased.

SUMMARY OF THE INVENTION

The problem is solved in accordance with the invention substantially inthat the sensor is a capacitive sensor with a first two-dimensional anda second two-dimensional electrode arranged inside the housing andpassing along at least one housing panel. In particular, it is providedthat the first and the second electrode run in one plane or in twoplanes that are parallel or approximately parallel to a housing panel,in particular to the housing front panel. The electrodes should herehave diverging two-dimensional extensions, in particular in the ratio of1:5 to 1:20, in particular 1:10. Here an electrode can have a surfacearea of, for example, 8 cm² and the other electrode a surface area of0.8 cm².

In particular, it is provided that the electrodes are at a distance fromone another that in its width extension is equal to or less than thenarrower electrode, which can also be described as strip-like. Theelectrodes themselves should have in the idle state, i.e. when the onlydielectric outside the housing is air, a capacitance of approximately 1pF±0.25 pF. If the dielectric then changes because a hand approaches,the change in capacitance will trigger a signal that in its turnactuates the towel dispenser. The electrodes forming the capacitor andrunning in one plane or if necessary in two parallel planes, i.e. offsetto one another, generate a virtually rectified field such that thecapacitance is affected whenever a change is made in the dielectricdistance up to approximately 30 mm from the surface of the toweldispenser housing by, for example, the approach of a hand. The capacitorformed by the electrodes running in one plane can be described as afolded-up panel-type capacitor.

The capacitive sensor generates in its surroundings an electrical fieldthat is changed by the approach of a hand. The change is evaluated andtriggers a pulse for actuating the issuing device. The dispensing devicecan therefore be used regardless of room-related light conditions orother environmental effects.

Also, for operating the issuing device it is only necessary for theelectrical field running between the electrodes to be changed in someway to the necessary extent, for example by an approaching hand, withoutthe need for contact with the housing at a certain spot or for the handto remain in a certain area. Functioning is also assured in rooms inwhich heavy soiling or high relative humidity occurs.

In a particularly preferred embodiment, it is provided that the sensoron the housing front side is arranged directly behind a front side ofthe housing. The arrangement of the sensor on the front ensures easyoperation of the dispensing device.

An arrangement on a different side or the alignment of one electrodeeach on a separate housing side is also possible, provided an effectiveand influencable field extends outside the housing.

In a further preferred embodiment of the dispensing device, it isprovided that the front side of the housing has at least one visualelement indicating a sensor field and/or a removal opening. It isprovided here that the visual element on the front side of the housingis designed as at least two recesses running horizontally. The recessesare preferably designed as semicircular and relief-like grooves. It isalso provided that the recesses divide the front of the housing in theratio of the golden section.

Apart from indicating the removal opening or localizing the sensor fieldor sensor surface, the recesses increase the stiffness of the housingsurface.

To rule out malfunctions of the dispensing device, the sensitivity ofthe capacitive sensor can be adjusted. For the simplest possible designof the sensor, it is proposed that it has a first and preferablytwo-dimensional electrode and a counter-electrode, both of which arearranged directly behind a front surface of the front side in order togenerate an electrical field outside the housing.

To ensure a mains-independent operation of the dispensing device, thelatter is equipped with a battery-powered drive device.

For simple maintenance and operation, a switch is arranged on the insideof the housing, using which the issuing device can be controlled whenthe housing is opened. Furthermore, a timer element is provided usingwhich the operation time of the issuing device can be adjusted.

An integrated time-lag element is also provided to determine a timeafter which the issuing device can be operated again. As an overloadprotection for a motor operating the issuing device, the circuit arrayhas an overcurrent protection.

In a mechanical embodiment of the dispensing device, a spring-loadedlever arm that can be operated from the front of the housing is providedthat has a rack for operating the issuing device. The rack here followsa circular path at whose centerpoint is the rotary axis of the lever.

For the issue of paper towels in the form of paper rolls, but also inthe form of single towels, it is provided that the issuing devicecomprises a puller roller and a pusher roller arranged opposite thereto,with the rack interacting with a gear arranged on the shaft of thepuller roller. Here the gear is designed with sleeve freewheel.

In the electrical embodiment of the issuing device, a motor with anassociated transmission is provided that engages in the gear arranged onthe shaft of the puller roller. The motor is here controlled by thesensor-operated control unit.

In particular, with an embodiment as a paper towel dispenser, with thepaper towels being rolled off a paper roll, a tear-off device isprovided, the latter being arranged on the inside of the housing and notbeing accessible from the outside. In this the embodiment in accordancewith the invention differs from the prior art, as in known devices thetear-off device is arranged on the front side of the housing, so thatinjuries are possible when pulling out or tearing off the paper towels.

Regardless of whether the dispensing device is operated electrically ormechanically, the housing has a number of advantages over the prior art.In a particularly preferred embodiment, it is provided that an upperside of the housing is angled about 8° from the horizontal towards thebeholder, so that rolling objects such as cigarettes cannot be rested onit.

Also, an intermediate field is provided between the upper side and thefront side and angled towards the mounting wall. In addition, housingvision panels are arranged on at least one side wall for observing theitems being dispensed. The housing is preferably made totally ofplastic.

Further details, advantages and features of the invention are shown notonly in the claims and in the features they contain—singly and/or incombination—but also in the following description of preferredembodiments shown in the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing,

FIG. 1 shows a perspective view of a towel dispenser,

FIG. 2 shows a sectional view of the dispensing device in accordancewith FIG. 1 in the electrical embodiment,

FIG. 3 shows a block diagram of a control circuit for the dispensingdevice in accordance with FIG. 2,

FIG. 4 shows a sectional view of the dispensing device in accordancewith FIG. 1 in a mechanical embodiment, and

FIG. 5 shows a plan view of electrodes of a capacitive sensor.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a perspective view of a sensor-operated electricaldispensing device 10 in the form of a paper towel dispenser withintegrated paper roll.

The dispensing device 10 has a housing 12 comprising a hood-like cover14 and a rear panel 16 attachable to a mounting wall (not shown). Thecover 14 is rotatably fastened to the rear panel 16.

The hood-like cover 14 comprises an upper side 18, a front side 20, alower side 22 and side surfaces 24, 26. Overall the surface of thehood-like cover 14 is closed, smooth and glossy, with the individualsides 18, 20, 22 being at different angles relative to one another, sothat a characteristic and dynamic appearance is obtained.

In particular, the upper side 18 is slightly inclined towards thebeholder at an angle of preferably about 8°, so that the placing orleaving of objects such as cigarettes and other rolling objects isprevented. A transitional area 28 or intermediate field is providedbetween the upper side 18 and the front side 20 and is inclined towardsthe mounting wall so that the optical appearance of the hood-like cover14 is matched to a removal opening 30 for towel removal arranged in thelower part of the front side 20.

The housing 12 shown in FIG. 1 is a housing for an electrically operateddispensing device with sensor activation. For visual indication of theremoval opening 30 and for localization of a sensor field 31, twohorizontally running recesses 32, 34 are provided in the front side 20of the cover 14. These are semicircular and relief-like grooves whichdivide the dispenser housing 12 in the golden section, so that abalanced appearance is obtained. The recesses 32, 34 designed as groovesof semicircular cross-section have a radius selected such that aflawless cleaning of the housing surface is assured. In addition to theinformative character of the recesses 32, 34 such as grooves, they alsoincrease the component rigidity, in particular of the front side 20.

To prevent a direct view into the removal opening 30, a housing surfacesection 36 in which the removal opening 30 has been provided is alsoinclined towards the mounting wall (not shown).

In both side panels 24, 26 of the hood-like cover 14, vision windows 37are provided to permit a check on how many unused towels are present inthe housing 12 by means of a notional arrow shape. The vision windowsare made of transparent plastic and are in two parts (erosion-typetexture/without texture), with a check mark to simulate the contour ofthe towel supply, such as the paper roll.

The rear panel 16 is completely enclosed by the hood-like cover 14, sothat it is not visible in the mounted state. An all-round rim (notshown) on a rear side of the dispenser ensures a spacing of approx. 2.5mm from the mounting wall, so that splash water, condensation etc. canrun off unhindered and not get inside the dispenser 10.

FIG. 2 shows a cross-section through the electrically operateddispensing device 10 in accordance with FIG. 1. Compared withconventional dispensing devices, the dispensing device 10 in accordancewith the invention is distinguished in that it has a capacitive sensor38, which in the embodiment is arranged directly behind the front side20. In particular, the capacitive sensor 38 has a two-dimensionalelectrode 40 and a counter-electrode 42 arranged behind a sensor field31 that is particularly emphasized by the horizontally running grooves32 and 34 on the front side. The arrangement of the capacitive sensor 38on the front side permits considerably more user-friendly handlingcompared with dispensing devices known from the prior art, since thesensor does not necessarily have to be arranged on the side.

The electrodes 40, 42 run parallel or approximately parallel to thesensor field 31 at least in some areas. The sensor field 31 can coverthe entire width of the housing.

Also, the sensor field can be in the area of the abutting front and sidesurfaces 20, 26 of the housing 10, and in the area of an edge of thehousing 10.

The capacitive sensor 38 is connected to an evaluation circuit arrangedon a PCB 44, as described in detail for FIG. 3.

A holder 46 extending from the rear panel 16 is provided and supports aroller 48 for receiving a towel roll, in particular a paper roll (notshown). For dispensing a section of the roll from the removal opening30, an issuing device 50 is provided.

The issuing device 50 comprises a puller roller 54 arranged on a shaft52 and opposite which a pusher roller 58 is arranged, also on a shaft56. In a gap 60 formed between the puller roller 54 and the pusherroller 58, a paper strip to be conveyed (not shown) is inserted, and ispassed to the outside through the removal opening 30 during operation ofthe puller roller 54.

For separation of the paper, a cutting edge 62 is provided that in theembodiment shown here is designed as a ZFN shaped angular section ofsheet metal with a toothed pattern. The teeth provided on a longitudinaledge 63 of the cutting edge are preferably designed with differinglengths.

The transported paper strip is passed along an arc-shaped guide surface34 in the direction of the removal opening 30.

In the embodiment shown here in accordance with FIG. 2, a torque istransmitted by means of a motor 66 that can be actuated using theelectric actuation device 44. The motor 66 has on the output side a gear68 that interacts via a further gear 70 with a gear 72 arranged on theshaft 52 of the puller roller 54.

Furthermore, a power supply unit 74 is provided that can be designedboth battery-powered and mains-powered.

In connection with the arrangement of the cutting edge 62 or tear-offedge, it must be noted that the latter is arranged on the inside of thehousing, so that if anyone reaches into the removal opening 30 contactwith the cutting edge 62 is ruled out or at least largely ruled out.

FIG. 3 shows a block diagram of a sensor-controlled motor control unit76. The motor control unit 76 has a power supply unit 78 with atransformer 80 and a first supply unit 82 for power supply to the sensor38 and a second supply unit 84 for power supply to the motor 66.

The capacitive sensor 38 comprises the first two-dimensional electrode40 and the counter-electrode 42 for generation of an electrical field.The sensor 38 is connected to an electronic control unit 88 which is inturn connected to a motor control circuit 90 that receives its energyfrom the second supply unit 84.

The electronic control unit 88 is furthermore connected to a trimmer 92used for setting the actuation time of the motor 66, which directlydetermines the paper length. Furthermore, a switch 94 is provided thatpermits manual actuation of the motor 66 when the cover 14 is opened tochange the paper. Overall, actuation of the motor 66 is only possiblewhen the cover 14 is closed. The closed position of the housing orhood-like cover 14 is picked up by a switch 96.

The motor control 90 directly controls the motor 66, which actuates theissuing device 50 via a transmission having the gears 68, 70. Concerningthe operating mode of the motor control unit 76, it must be noted thatthe approach of a hand changes the electrical field formed between theelectrodes 40 and 42, in particular the dielectric constant of thedielectric otherwise formed by air, and that the change is registered bythe electronic control unit 88 and processed into a control signal.Depending on the actuation time set using the trimmer 92, the motor 66is operated for a certain period so that a paper strip of predeterminedlength is dispensed.

All components of the control circuit 76 are designed with SMDtechnology. Also, the complete circuit including the electrodes 40, 42is arranged on a PCB. It must be mentioned that it is particularlyadvantageous for the PCB 44 and the electrodes 40 and 42 to be arrangedinside the housing 12 and hence to be neither visible nor accessiblefrom the outside. Also, the control circuit 76 can be arranged with theelectrodes 40, 42 in a separate housing, thus providing additionalprotection and, in the case of a fault, easy maintenance; for example,in the case of a fault in the electronic circuit the housing has only tobe removed and then replaced by a new and correctly functioning unit.

To provide a dispensing preventer to stop repeated operation, anintegrated time-lag element is provided, with the time lag also beingadjustable using a trimmer. Furthermore, an overcurrent protectioncircuit is provided so that when the motor is blocked, for example by apaper jam or clogging, the electronic unit is protected againstexcessive current.

As shown in FIG. 5, the electrodes 40, 42 are designed approximatelyrectangular and have surface ratios of preferably 1:10. For example, oneof the electrodes—in the embodiment the electrode 40—can have a surfacearea of 8 cm² and the other electrode 42 a surface area of 0.8 cm². Thecapacitor formed by the electrodes 40, 42 should then have—when thedielectric is not influenced by a hand for example, i.e. is in the idlestate—a capacitance of approximately 1 pF±0.25 pF. If there is then achange in the dielectric, for example by a hand approaching the housing12 and in particular the sensor field 31, a change in the capacitanceresults from the change in the dielectric and triggers a switchingoperation for dispensing a section of towel, in particular a papertowel, pulled off a roll.

As FIG. 5 already makes clear without a detailed description, theelectrode 40 is rectangular and the electrode 42 is of strip-like form,said electrodes 40, 42 having a spacing 41 that is narrower than theelectrode 42. If a surface of a unit 1 is bounded by the electrodes 40,42 including the spacing 41, the electrode 40 takes up about 80% of thisarea, the strip-like spacing 41 about 5% and the strip-like electrode 42about 15%. As a result the required rectified electrical field extendingto the outside of the housing 12 is generated.

By the design of the electrodes 40, 42, in particular of their differentsizes and arrangement in a plane running parallel to a housing panel, inparticular to the front housing side 20 or to the sensor surface 31, arectified electrical field extending to the housing exterior isgenerated and is effective to the required extent for triggering acontrol command whenever a hand for example moves into the area up to 30mm from the front side 20 or sensor surface 31, without the need fordirectly touching the front side 20 or the sensor surface 31.

FIG. 4 shows a sectional view of a mechanically actuatable dispensingdevice 100. It must be noted here that the form of the housing 12corresponds mainly to the form of the electrically operated dispenser10. In particular, the same issuing device 50 is used as alreadydescribed with reference to FIG. 2.

In accordance with the invention, a lever arm 102 is provided formechanical actuation of the issuing device 50 and is pivotably mountedin the inside of the housing 12 on an axis 104. On the outside of thehousing a handle 106 is provided that is connected to the lever arm 102and is movable substantially parallel to a surface 108 on the front side20 of the housing 12 for operation of the lever arm 102. For verticalmovement of the lever arm 102, a slot-like and substantially verticalopening 110 is provided in the front side 20.

One end 112 of the lever arm 102 opposite the axis 104 is provided witha rack 114 following an arc-shaped path, with the arc-shaped rack 114interacting with the gear 72 arranged on the shaft 52 and exerting atorque on the puller roller 54 when the lever arm 102 is actuated. Thereturn of the lever arm 102 to its original position is achieved using aspring 116, which is for example designed as a torsion spring and isarranged coaxially to the axis. It is provided here that the gear 72 isdesigned with sleeve freewheel, so that no torque is transmitted by thefreewheel movement to the puller roller 54 in the event of an upwardmovement of the lever arm or curved rack 114.

With the teachings in accordance with the invention, easy-to-operate andfault-resistant towel dispensers are provided, and the servicing costsare reduced by easy maintenance and the use of only a few elementssubject to wear. The design in accordance with the invention alsopermits simple conversion from mechanically to electrically operatingpaper dispensers and vice versa.

The housing 12 is preferably made of an impact-resistant andcorrosion-resistant plastic whose stability is increased by edging andbeading. The provision of an internal sensor in accordance with theinvention means than external and fault-prone sensors can be dispensedwith.

What is claimed is:
 1. A paper towel dispenser (10, 100), comprising: a housing (12) in which a towel receiver and a towel issuing device (50) are provided, said issuing device being actuatable by a sensor (38) activatable from the housing exterior, wherein the sensor is a capacitive sensor (38) with a first two-dimensional and a second two-dimensional electrode (40, 42) having different surface areas arranged inside the housing (12) and passing along at least one housing side (20).
 2. Towel dispenser according to claim 1, wherein the first and the second electrode (40, 42) are coplanar or disposed in two planes that are parallel to the housing front side (20).
 3. Towel dispenser according to claim 1, wherein the surfaces areas of the electrodes (40, 42) being in a ratio of approximately 1:5 to 1:20 and wherein the electrodes have a spacing (41) therebetween equal to or less than the width of the second electrode (42).
 4. Towel dispenser according to claim 1, wherein the electrodes (40, 42) are arranged directly behind a housing panel and extend at least in some areas parallel or approximately parallel to a sensor field (31) provided in the housing panel, in the area of which an electrical field running between the electrodes can be influenced.
 5. Towel dispenser according to claim 1, wherein the sensor (28) is arranged directly behind the housing front side (20).
 6. Towel dispenser according to claim 1, wherein the front side (20) has at least one visual element (32, 34) indicating a sensor field (31) or a removal opening (30).
 7. Towel dispenser according to claim 6, wherein the visual element on the front side (20) of the housing (12) is designed as at least two recesses (32, 34) running horizontally, the recesses dividing the front side of the housing in the golden section ratio.
 8. Towel dispenser according to claim 1, wherein the towel dispenser (10) is battery-operated.
 9. Towel dispenser according to claim 1, wherein the towel dispenser (10) has a switch (94) on the inside of the housing with which the issuing device (50) can be operated when the housing is open.
 10. Towel dispenser according to claim 1 with a tear-off device extending from the housing interior in the area of the issuing device (50), wherein the tear-off device (62) is not accessible from the housing exterior and wherein the tear-off device comprises a Z-shaped angular section extending parallel to a rotary axis of a paper roll and wherein the tear-off device includes a free longitudinal edge with teeth of differing length.
 11. Towel dispenser according to claim 1, comprising a cover having an upper side angled about 8° from the horizontal.
 12. Towel dispenser according to claim 1, including first and second side panels (24, 26) having vision windows (38).
 13. Towel dispenser according to claim 11, wherein the hood-like cover (14) is rotatably fastened to and lockable to a rear panel (16).
 14. Towel dispenser according to claim 1, wherein the capacitive sensor (38) has an adjustable sensitivity.
 15. Towel dispenser according to claim 1, wherein upon actuation the issuing device (50) issues paper towels for an adjustable period of time. 